This invention is generally directed to toner and developer compositions, and more specifically, the present invention is directed to developer and toner compositions containing resins wherein the charge enhancing functionality is incorporated in the main chain of the polymeric resin, and which resins, for example, impart or assist in imparting a positive or negative charge to the toner resin particles and enable toners with rapid admix characteristics. In embodiments, there are provided in accordance with the present invention toner compositions comprised of resin particles, pigment particles, and wherein the polymeric toner resin contains a functional moiety such as a distearyl dimethyl ammonium 2,4-isophthaloyl sulfonate, sodio 2,4-isophthaloyl sulfonate, or calcio 2,4-isophthaloyl sulfonate and the like; and which resin imparts or assists in imparting negative charge characteristics to the toner resin particles and enable toners with rapid admix characteristics such as less than 60 seconds. More specifically, in embodiments of the present invention, there is provided a toner comprised of pigment particles and a polyester resin containing the functional charge enhancing functionality as illustrated by the formula ##STR2## wherein X is an alkaline ion such as H+, Na+, Li+, K+, Rb+, or Cs+; an alkaline earth metal such as Be.sup.2 +, Mg.sup.2 +, Ca.sup.2 +, Sr.sup.2 +, or Ba.sup.2 +; a metal such as V.sup.2 +, Cr.sup.2 +, Zr.sup.2 +, Mn.sup.2 +, Fe.sup.2 +, Fe.sup.3 +, Co.sup.2 +, Ni.sup.2 +, Zn.sup.2 +, Ag+, Cd.sup.2 +, or an ammonium cation such as H.sub.4 N+, or R".sub.4 N + wherein R" is an alkyl or arylalkyl group of from about 1 carbon atom to about 40 carbon atoms; R is alkylene, cyclohexyl, bisphenol, bis(alkyloxyl), or oxyalkylene; and R' is an alkylene, an arylene, or cycloalkylene group of from about 1 carbon atom to about 40 carbon atoms. Alkylene includes components with from 1 to about 40 carbon atoms like ethylene, propylene, butylene, hexylene, and the like; arylene includes groups with from about 6 to about 30 carbon atoms like phenylene, biphenylene, anthralene, and the like; and cycloalkylene of from about 1 to about 40 carbon atoms like cyclohexylene, 1,4-dimethylcyclohexylene, cyclopentylene, and the like.
The toner compositions and developer thereof, that is the toner mixed with the carrier, displays negative charge characteristics such as from about -10 to -45 microcoulombs per gram and preferably of from about -10 to -40 microcoulombs per gram, or positive charge characteristics such as from about 10 to 45 microcoulombs per gram and preferably of from about 10 to 40 microcoulombs per gram. Also, the aforementioned developer compositions display rapid admix of less than about 60 seconds, extended developer life, stable electrical properties, high image print quality with substantially no background deposits, excellent relative humidity sensitivity such as from about 1.2 to about 2.5, and compatibility with fuser rolls including VITON.RTM. fuser rolls. Also, the aforementioned toner compositions usually contain pigment particles comprised of, for example, carbon black, magnetites, or mixtures thereof, cyan, magenta, yellow, blue, green, red, or brown components, or mixtures thereof thereby providing for the development and generation of black and/or colored images. The toner compositions of the present invention in embodiments thereof possess excellent admix characteristics as indicated herein, and maintain their triboelectric charging characteristics for an extended number of imaging cycles up to, for example 1,000,000 in a number of embodiments. The toner and developer compositions of the present invention can be selected for electrophotographic, especially xerographic imaging and printing processes, including color processes.
Developer compositions with charge enhancing additives, which impart a positive, or negative charge to the toner resin, are known. Thus, for example, there is described in U.S. Pat. No. 3,893,935 the use of quaternary ammonium salts as charge control agents for electrostatic toner compositions. In this patent, there are disclosed quaternary ammonium compounds with four R substituents on the nitrogen atom, which substituents represent an aliphatic hydrocarbon group having 7 or less, and preferably about 3 to about 7 carbon atoms, including straight and branch chain aliphatic hydrocarbon atoms, and wherein X represents an anionic function including, according to this patent, a variety of conventional anionic moieties such as halides, phosphates, acetates, nitrates, benzoates, methylsulfates, perchloride, tetrafluoroborate, benzene sulfonate, and the like; U.S. Pat. No. 4,221,856 which discloses electrophotographic toners containing resin compatible quaternary ammonium compounds in which at least two R radicals are hydrocarbons having from 8 to about 22 carbon atoms, and each other R is a hydrogen or hydrocarbon radical with from 1 to about 8 carbon atoms, and A is an anion, for example sulfate, sulfonate, nitrate, borate, chlorate, and the halogens such as iodide, chloride and bromide, reference the Abstract of the Disclosure, and column 3; a similar teaching is presented in U.S. Pat. No. 4,312,933 which is a division of U.S. Pat. No. 4,291,111; and similar teachings are presented in U.S. Pat. No. 4,291,112 wherein A is an anion including, for example, sulfate, sulfonate, nitrate, borate, chlorate, and the halogens. There are also described in U.S. Pat. No. 2,986,521 reversal developer compositions comprised of toner resin particles coated with finely divided colloidal silica. According to the disclosure of this patent, the development of electrostatic latent images on negatively charged surfaces is accomplished by applying a developer composition having a positively charged triboelectric relationship with respect to the colloidal silica.
Also, there is disclosed in U.S. Pat. No. 4,338,390, the disclosure of which is totally incorporated herein by reference, developer compositions containing as charge enhancing additives organic sulfate and sulfonates, which additives can impart a positive charge to the toner composition. Further, there is disclosed in U.S. Pat. No. 4,298,672, the disclosure of which is totally incorporated herein by reference, positively charged toner compositions with resin particles and pigment particles, and as charge enhancing additives alkyl pyridinium compounds. Additionally, other documents disclosing positively charged toner compositions with charge control additives include U.S. Pat. Nos. 3,944,493; 4,007,293; 4,079,014; 4,394,430 and 4,560,635 which illustrates a toner with a distearyl dimethyl ammonium methyl sulfate charge additive. One disadvantage associated with the charge additive of the '635 patent resides in its apparent inherent instability in some instances thus rendering it substantially unsuitable as a bulk toner constituent in imaging processes, as the additive can thermally and chemically degrade and react with other toner components.
The following United States patents are also mentioned: U.S. Pat. No. 4,812,381 which discloses toners and developers containing charge control agents comprising quaternary ammonium salts of the formula indicated, for example, in the Abstract of the Disclosure, wherein R is alkyl with from 12 to 18 carbon atoms, and the anion is a trifluoromethylsulfonate; a similar teaching is presented in U.S. Pat. No. 4,834,921; U.S. Pat. No. 4,490,455 which discloses toners with, for example, amine salt charge enhancing additives, reference the Abstract of the Disclosure, for example, and wherein na is an anion including those derived from aromatic substituted sulfonic acids, such as benzene sulfonic acid, and the like, see column 3 beginning at line 33; U.S. Pat. No. 4,221,856 directed to toners with a quaternary ammonium compound wherein A is an anion such as sulfate, sulfonate, nitrate, borate, chlorate, and certain halogens, see the Abstract of the Disclosure; Reissue U.S. Pat. No. 32,883 (a reissue of U.S. Pat. No. 4,338,390) illustrates toners with sulfate and sulfonate charge additives, see the Abstract of the Disclosure, wherein R.sub.4 is an alkylene, and the anion contains a R.sub.5 which is a tolyl group, or an alkyl group of from 1 to 3 carbon atoms, and n is the number 3 or 4; U.S. Pat. No. 4,323,634 which discloses toners with charge additives of the formulas presented in column 3, wherein proving that at least one of the R's is a long chain amido group, and X is a halide ion or an organosulfur containing group; U.S. Pat. No. 4,326,019 relating to toners with long chain hydrazinium compounds, wherein the anion A can be a sulfate, sulfonate, phosphate, halides, or nitrate, see the Abstract of the Disclosure for example; U.S. Pat. No. 4,752,550 which illustrates toners with inner salt charge additives, or mixtures of charge additives, see for example column 8; U.S. Pat. No. 4,684,596 which discloses toners with charge additives of the formula provided in column 3 wherein X can be variety of anions such as trifluoromethane sulfonate; and U.S. Pat. Nos. 4,604,338; 4,792,513; 3,893,935; 4,826,749 and 4,604,338. The disclosure of each of the aforementioned patents is totally incorporated herein by reference.
The following prior art, all U.S. patents, are also recited: U.S. Pat. No. 4,812,381 relating to toners and developers with quaternary ammonium salts of the formula illustrated in column 3, the preparation thereof, see column 4, and also note the working Examples, columns 7 and 8, wherein specific charge additives, such as octadecyl ammonium trifluoromethane sulfonate, are reported; U.S. Pat. No. 4,752,550, the disclosure of which is totally incorporated herein by reference, directed to toners and developers with inner salt charge additives and mixtures of such salts with other charge additives, see for example column 4; and Reissue U.S. Pat. No. 32,883 (a reissue of U.S. Pat. No. 4,338,390), the disclosures of which are totally incorporated herein by reference, wherein toners with organic sulfonate and organic sulfate charge enhancing additives are illustrated, see columns 3, 4, and 5 to 10 for example.
Moreover, toner compositions with negative charge enhancing additives are known, reference for example U.S. Pat. Nos. 4,411,974 and U.S. Pat. No. 4,206,064, the disclosures of which are totally incorporated herein by reference. The '974 patent discloses negatively charged toner compositions comprised of resin particles, pigment particles, and as a charge enhancing additive ortho-halo phenyl carboxylic acids. Similarly, there are disclosed in the '064 patent toner compositions with chromium, cobalt, and nickel complexes of salicylic acid as negative charge enhancing additives. A number of other patents illustrate toners with charge additives, such as U.S. Pat. No. 4,845,003 wherein toners with aluminum complexes, such as BONTRON E-88.TM. are illustrated.
There is illustrated in U.S. Pat. No. 4,404,271 a complex system for developing electrostatic images with a toner which contains a metal complex represented by the formula in column 2, for example, and wherein ME can be chromium, cobalt or iron. Additionally, other patents disclosing various metal containing azo dyestuff structures wherein the metal is chromium or cobalt include U.S. Pat. Nos. 2,891,939; 2,871,233; 2,891,938; 2,933,489; 4,053,462 and 4,314,937. Also, in U.S. Pat. No. 4,433,040, the disclosure of which is totally incorporated herein by reference, there are illustrated toner compositions with chromium and cobalt complexes of azo dyes as negative charge enhancing additives.
While many charge enhancing additives are known, there continues to be a need for toners wherein charge enhancing additives can be avoided. It is known that the addition of charge enhancing additives to toners, such as distearyl dimethyl ammonium methyl sulfate and the like can increase the minimum fixing temperature of the resin, accompanied by narrowing of fusing latitude and blocking characteristics. In the present invention, the use of separate charge enhancing additive compounds are avoided since the toner contains a polymeric resin comprised of a charge enhancing functional moiety capable of providing negative charging characteristics such as from about -10 to about -40 microcoulombs per gram, or provide positive charging characteristics such as from about 10 to about 40 microcoloumbs and fast admix times such as less than 30 seconds without increasing the minimum fixing temperature, or narrowing the fusing latitude or reducing blocking characteristics. In embodiments, negative triboelectricals can result with Xerox Corporation carriers available as 9200 carrier comprised of a steel core with a polyvinylidene coating of 0.75 weight percent, and positive tribos result with, for example, Xerox Corporation 1075 and 5090 carriers comprised, for example, of oxidized steel core grit with 0.175 percent of KYNAR.RTM. coating or steel with two polymer coatings of KYNAR.RTM./PMMA.
Also, there is a need for toner compositions which have the desired triboelectric charge level, for example, from about 10 to about 40 microcoulombs per gram, and preferably from about 10 to about 25 microcoulombs per gram, and admix charging rates of from about 5 to about 60 seconds, and preferably from about 15 to about 30 seconds, as determined by the charge spectrograph, preferably, for example, at low concentrations, that is, for example, less than 1 percent, and preferably less than about 0.5 percent of the charge enhancing additive of the present invention and wherein the toners possess excellent humidity sensitivity at relative humidities of from about 20 to about 80 percent, and wherein during toner extrusion processing the use of separate charge additives can be avoided. Furthermore, there is a need for toner compositions which do not require charge enhancing additive during the extrusion process, which tends to generate toners with a nonhomogeneous incorporation of charge enhancing additives.